Charged particle production in Pb-Pb collisions at the LHC with the ALICE detector

The charged particle multiplicity is measured in |η|<0.5 to be dNch/dη=1601±60 in 5% most central Pb-Pb collisions, indicating an energy density a factor ∼ 3 higher than at RHIC. Its evolution with centrality shows a pattern strikingly similar to the one measured at RHIC. Intermediate (5≲pT≲15 GeV/c) transverse momentum particles are found to be most strongly suppressed with respect to pp collisions, consistent with a large energy loss of hardscattered partons in the hot and dense medium. The results are presented in terms of the nuclear modification factor RAA and compared to theoretical expectations.